The overall objective of this proposal is to identify key mechanisms by which adult human non-neoplastic prostate epithelial cells are driven towards increasingly malignant phenotypes. Characterization of molecular and cytogenetic modifications which may correlate with the malignant potential of human prostate tumor cells will be undertaken. The following are the specific aims of this proposal: (10 To immortalize adult human non-neoplastic prostatic epithelial cells from in vitro by transfection of specific transforming genes of SV40 or Human Papilloma Viruses (HPV). Histopathologically confirmed nonneoplastic prostatic tissue obtained surgically will be the source of cells. (2) To drive these cells further toward complete tumorigenicity by exposure in vitro to chemical agents implicated in prostatic carcinogenesis. Emphasis will be placed upon the impact of treatment with both direct (MNNG, ) and indirect (benzo[a]pyrene) carcinogens. (3) At each stage of tumor evolution, the resulting cells will be characterized in terms of morphology, in vitro growth capacity, cytogenetics, and immunocytochemically detectable marker proteins (epithelial cytokeratins, prostate specific antigen, prostatic acid phosphatase, epidermal growth factor receptor, androgen receptor, etc.). In addition, tumorigenicity will be evaluated by ability to grow progressively as a tumor in athymic nude mice. (4) Insights into prostatic epithelial cell transformation generated by these experiments will be investigated for relevence to the natural history of human benign and malignant neoplasms. These studies will facilitate our understanding of the most common tumor occurring among American men, and thus may lead to new opportunities for therapeutic intervention in a disease for which there are no satisfactory treatment options.